1. Technical Field
The present invention relates to a printing device and to a printing method.
2. Related Art
Printing devices that employ an inkjet system whereby printing onto a medium (such as paper, fabric, or OHP transparency film) is carried out by expelling ink from a head on which a multitude of nozzles are arrayed are known in the art. Known printing devices of this kind include line printers, in which the medium is fed with respect to a stationary head; and serial printers, in which an operation of moving the head while expelling ink and an operation of feeding the medium are repeated in alternating fashion. Known systems for expelling ink from the head include piezoelectric systems employing piezoelectric elements such as piezo elements, and thermal systems that employ a heater to create bubbles.
In inkjet system printing devices, dots are formed on a medium by ink that has landed on the medium, to effect printing onto the medium of an image (printed image) composed of a multitude of these dots. In some instances, streak-like density unevenness may occur in printed images. It is thought that such density unevenness is caused by failure of the multitude of dot rows making up a printed image from being formed in ideal fashion due to the effects of manufacturing errors of the heads, so that individual dot rows are darker or lighter depending on dot size, or the dot rows are formed out of alignment.
Density unevenness correction technologies like that disclosed in Japanese Laid-Open Patent Application 2005-205691, for example, are known methods for reducing such density unevenness.